Altera Floating-Point Manuel d'utilisateur télécharger pdf (Page 59)

Table 6-4: Summary of Input Values and Corresponding Outputs

This table lists the inputs and corresponding outputs obtained from the simulation in the waveform.

Time Event

0 ns, start-up dataa[] value: 0000 0000h

datab[] value: 0000 0000h

Output value: The undefined value is seen on the result[] port, which is ignored.

All values seen on the output port before the 6th clock cycle are merely due to the

behavior of the system during start-up and should be disregarded.

17600 ns Output value: 7FC0 0000h

Exception handling ports: nan asserts

The division of zeros result in a NaN.

2000 ns dataa[] value: 2D0B 496Ah

datab[] value: 3A5A FC26h

Both inputs hold normal values.

20800 ns Output result: 321F 6EC6h

Exception output ports: nan deasserts

The division of two normal value results in a normal value.

11000 ns dataa[] value: 046E 78BCh

datab[] value: 6798 698Bh

Both inputs hold normal values.

27200 ns Output value: 0h

Exception handling ports: underflow and zero asserts

The division of the two normal values results in a denormal value. As denormal

values are not supported, the result is zero and the underflow port asserts. The zero

port is also asserted to indicate that the result is zero.

2600 ns dataa[] value: 0D72 54A8h

datab[] value: 0070 0000h

The input port dataa[] holds a normal value while the input port datab[] holds a

denormal value.

36800 ns Output value: 7F80 0000h

Exception handling ports: division_by_zero asserts

Denormal numbers are forced-zero values, therefore, attempts to divide a normal

value with a zero result in an infinity value.

UG-01058

2014.12.19

ALTFP_DIV Design Example: Understanding the Simulation Results

6-5

ALTFP_DIV IP Core

Altera Corporation

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Altera Floating-Point Manuel d'utilisateur Page 59